Modern Vespa

Hi all. Have vespa gts 300. Drive it 20 mile. 70 mile then lack power. Wont ref. Asr starts flashing. No power. Turn ignition off. Turn ignition on. Pull brake and press calibrate switch. Ars light up. Has full power again. Anyone no why it does this. Thanks

Have you tried resetting the ASR? This should be done every so often.

https://members.modernvespa.net/grun253/uploads/vespa_gts300_2015_abs_233_18895.pdf

Certainly sounds like the ASR system is activating for some reason after riding a distance. I believe the ASR is triggered by the ABS wheel speed sensors, so maybe you have a wire fault or sensor fault that only occurs when parts warm up? Might be time to put a reader onto the bike and scan for faults.

check tire pressures

Interesting suggestion Steelbytes. Are you suggesting the underinflaed tyres are getting hot and expanding and that is setting off the ASR due to the change in relative rotational speed? Sounds possible. I do know the back tyre on my GTS gets a lot hotter than the front.

Based on the description I wasn't assuming temp changes being the cause but rather simply one of the tires has gone half flat (or alternatively been pumped too high). Certainly there has been many people who have had ASR problems due to incorrect tire inflation.

PS, yes heat does cause a lot of psi variation in particularly on the rear wheel which can easily have a 10psi / 50C variance on a long day ride (real numbers from my tpms)

My reason for the suggestion about heat is that the OP stated that the ASR fault only kicked in after 20 miles. If it was just low inflation, the fault would probably happen from the off. I assume the ASR would only be triggered if the rear wheel speed exceeded the front by a margin (=wheelspin).

I'm also quite familiar with pressure rises from running; my heavy ST1300 torments back tyres and they can rise by 12 psi sometimes. I now routinely overinflate the tyre to minimise the rise and improve tyre life but 6000km of enthusiasm is the normal limit.

Can confirm: spent a week trying to figure out why the ASR was acting up on my ride (without checking the rear pressure) only to realize the tire was the issue when the slow leak turned into a full flat.

Yes, I know, very stupid to not check the pressure more regularly. I'm reformed.

Hi.vespa gts300. Still have e problem when hot. Abs light on. Loses power. Turn ignition of. Ignition Back on . Hold brake. Asr light comes on. Back to full power. Thanks. Any suggestions

Yes, in order not to be activated, the service told me to adjust the front wheel 30 pressure rear wheel 32 pressure every 15 days. Whenever I didn't do this, the asr was always activated.

some were given

What are your tire pressures front and rear in psi or bar?

Oh FFS.

1) Please tell us what your tyre pressures are.

2) Please tell us if you have then, with *correct tyre pressures* calibrated the ASR according to the manual that you surely must have in your hand...

So far all you have done is complain.